The present invention relates to a seating unit having a seat and a reclineable back, both having support surfaces constructed for comfort and excellent ergonomic support in all positions of the seat and back.
Comfort continues to be a highly-demanded feature in seating. One reason for this is because businesses have found that workers are more productive and creative when they are comfortable. However, “comfort” is an illusive criterion. Not only do people have different body shapes, but people also have dramatically different preferences. The task of providing comfort for chairs having reclineable backs is even more difficult, since they must provide support to a seated user in upright, intermediate, and reclined positions. This is particularly difficult because, as a person reclines, the shape of his/her body changes, and the pressure points of support change. For example, as a person reclines, their pelvis rotates, causing a change in the shape and location of the bone structure that receives the support from the seat and back of the chair. Further, seated users often stretch, turn, and reach from side-to-side, such that uniform support transversely across the seat does not necessarily provide optimal support or optimal comfort. Merely providing a thick foam cushion to eliminate point stress is not a satisfactory solution, since foam does not breathe, is environmentally unfriendly, and may not provide the level of distributed support needed in certain areas. For example, foam cannot easily be made to provide stiffer support under a seated user's pelvis, and lesser support under the user's knees, since it is not easy to control foam in a manner causing selectively different densities in different areas. Additionally, foam cushions that are thick enough to provide “adequate” support may not fit aesthetically with a chair designed to have a thin, sleek appearance. Adjustable chairs also do not satisfactorily solve the problem of discomfort from point stresses, since users tend to improperly adjust chairs, or not adjust them at all. Further, many seated users are not sure how to adjust their chairs for optimal comfort. Nonetheless, seated users know when they are comfortable and when they are not.
Chair comfort is particularly important for computer and keyboard operators and for task-related jobs where the operator stays seated, since such users often stay in their chairs for extended periods of time. It is important that these seated users be able to move around in their chairs while continuing to do work-related tasks, since movement is important for good circulation and good health and to avoid back problems. One type of chair in particular where good support is desired while doing work-related tasks is a task chair having a reclineable back. It is known to provide a weight-activated feature on such chairs so that heavier users automatically receive additional support upon recline without having to adjust a tension device on a back support. For example, some chairs include a seat that lifts during back recline, so that the user's own weight helps provide a force to resist recline of the back. However, these chairs suffer from various types of problems. Where the front of the seat is lifted, an uncomfortable pressure is placed at the seated user's knees, under the seated user's thighs. Where a rear of the seat is lifted, the user feels a tendency to slide down its inclined back and forward out of the seat, especially if the seat is tipped forward. Even if the seat remains in a horizontal orientation, an angled/reclined back directs a weight of the seated user at a forward angle relative to the seat, such that the seated user tends to slide down the back and slide forward on the seat, with only the friction of their body on the seat and back holding them in place.
In addition, it is also desirable to provide a surface-supporting structure that is simple to manufacture and assemble, is low-cost, and that has a modern, thin, sleek appearance. It is further desirable that the surface-supporting structure compliment the ability to provide weight-activated support upon recline so that heavier seated users feel secure upon recline even without adjustment.
In addition to the above, it is desirable to provide a chair that is optimally designed to use recyclable parts, recyclable materials, and that uses components that can be easily separated for recycling and/or repair. Expanded thermoset urethane foam products are usually classified as not recyclable, and further are generally considered to be unfriendly to the environment as compared to steel, remeltable thermoplastic, recyclable materials, and or more natural materials. Eliminating thermoset foam would be a significant step toward making a chair 100% recyclable. However, any such change must maintain a high level of comfort and cost advantage for competitive reasons.
Accordingly, an apparatus solving the aforementioned problems and having the aforementioned advantages is desired.